Usually, the treatment of bone sarcomas includes several types of therapy. It is therefore necessary, that the treatment strategy and decision is discussed and taken among a so-called multidisciplinary team of medical and radiation oncologists, surgeons, radiologists and experts from other disciplines if necessary.

The treatment strategy depends on different aspects: type of bone cancer, stage of disease (localized = tumour is limited to the primary location vs. metastatic disease = has already spread to other organs) and general health status of the patient. Patients may face choices, including entry into a clinical trial, and will probably need detailed information from the treatment team.

Surgery

Surgery is considered standard therapy for localized bone sarcomas in order to (ideally) remove the tumour completely. This is the best chance to cure the patient. The surgeon will cut out the tumour as well as some normal tissue (so-called margins) in order to make sure that no tumour cells remain in the body. This reduces the risk of (local) recurrence.

Operating on the tumour and cutting out enough normal surrounding tissue can sometimes be difficult if it is located in a limb (arm or leg). An amputation may be considered if removing all of the cancer requires removing essential nerves, arteries, or muscles that would leave the limb without good function. However, nowadays, a complete amputation – removal of a part or all of a limb – is rare. Specialized surgeons will aim to avoid amputation and conduct so-called limb-salvage or limb-sparing surgery, which removes the cancer but leaves a working arm or leg. Artificial bones (endoprosthetics) are increasingly used to replace bones damaged by tumours. In children there are techniques which allow endoprosthetic bones to be extended to match natural growth. Some of these techniques are non-invasive, i.e. they do not involve further surgery. More than 90 % of bone cancer patients with a limb affected are able to have their limb spared.

For tumours in other places such as pelvis or jaw, the removed bone will be replaced by either bone grafts or bones from other parts of the body. It is hoped in future that computer 3D printing may help surgeons by providing artificial bone replacements but this is still an idea. In parts of the body where bone replacement is difficult, e.g. in the skull, additional local treatments might be applied, among them curettage (scooping out the tumour without removing the bone), cryosurgery (killing cancer cells with extreme cold using liquid nitrogen) and bone cement (a liquid that hardens over time, giving off a lot of heat which helps kill any remaining tumour cells e.g. after curettage).

Surgery is also an option in metastasized disease. Especially in the lung (most common site of bone cancer metastasis), surgeons might be able to remove all metastasis. However, this has to be carefully planned and depends on a range of factors which includes site, number and size of metastases, rate of growth, duration of disease and the patient’s age and general health.

Radiotherapy

Radiation therapy is applied regionally or locally to destroy tumour tissue. However, most bone cancers (apart from Ewing sarcomas) are not very sensitive to radiation. That is why radiation is preferably a major treatment option for Ewing’s sarcoma.

Radiation therapy in bone cancers may be considered before or after surgical treatment (most common in bone sarcomas): Before surgery (neoadjuvant treatment) it may be used to try to shrink a large tumour until it is possible to remove it completely without an amputation. During surgery, trials have been conducted involving removal of a bone with a small tumour, intensive single-dose radiation treatment of the bone, and the bone being replaced in the patient. After surgery (adjuvant treatment) it aims at avoiding either local or regional recurrences, which may develop from microscopic cells left over after surgery, or at destroying adjacent lesions that could not be surgically removed. Rarely, it may be performed instead of surgery to achieve local control of the tumour although this is a palliative approach.

Ewing’s sarcoma presents many challenges for radiotherapy oncologists when tumours are on or in the body. Pelvic radiotherapy has a high morbidity and can result in loss of fertility in women and other side effects for all patients. To avoid this there is growing use of proton beam therapy to treat young women and preserve fertility. As there are very few proton beam facilities in Europe at present this involves extensive co-ordination, travel and costs.

Radiotherapy in advanced disease can be used to relieve symptoms, prevent complications or control metastasis, especially bone metastasis.

Unlike radiotherapy or surgery which are localized therapies, chemotherapy is a so-called systemic treatment: It is applied into the bloodstream and affects the whole body.

For osteosarcoma and some of the less common bone sarcomas neo-adjuvant chemotherapy is used as an induction treatment prior to surgery. The aim is to kill the tumour. The degree of necrosis (tumour cell death) which has been achieved can be assessed by the pathologist following surgery and is a good prognostic indicator. Further chemotherapy will be given adjuvant to surgery as this has been shown in clinical trials to lead to the best chance of a cure.

In Ewing’s sarcoma chemotherapy is usually given before and after surgery, sometimes in combination with radiotherapy. However, chordoma and giant cell tumours of the bone do not respond well to chemotherapy and it is also mostly not considered for localized chondrosarcomas.

Chemotherapy plays a major role in the advanced and metastatic setting. There are different drugs currently available: doxorubicin and other anthracyclines, cisplatin, ifosfamide, cyclophosphamide, gemcitabine, docetaxel, etoposide, methotrexate, irinotecan, dactinomycin, vincristine and other vinca alkaloids.

In some types of bone cancer, targeted drugs might be beneficial. These new agents inhibit tumour growth. Among them are Imatinib in advanced chordoma and Denosumab in recurrent or non-resectable giant cell tumours. However, none of these drugs is approved by the FDA (Food and Drug Administration, USA) or the EMA (European Medicines Agency) for these types of cancer and they usually have to be applied ‘off-label’ where this is permitted. Further new approaches are currently tested in (early) clinical trials.

Targeted Therapies

New insights from molecular biology and biomedicine reveal certain features and characteristics of malignant cells which can be targeted by the development of new, specific drugs. For example, cancer cells usually show changes in their genetic material (= mutations) which lead to altered protein structures where either the cause can be inhibited or the effect can be treated.

Since these characteristics do not (or only rarely) show up in normal cells, targeted therapy specifically fights cancer cells and spares healthy cells. This approach usually makes it both effective and less toxic than chemotherapy.

Osteosarcoma

Osteosarcoma is a cancerous tumor that occurs in the bone. Osteosarcoma is a primary bone cancer. That means the cancer originates in the bone itself.

Most osteosarcomas appear in the long bones of the body, such as the femur (the thigh bone), the tibia (the shinbone) or the humerus (the bone that runs from the shoulder to the elbow), although they can appear in any bones.

Osteosarcoma is the oldest cancer known to man. A fossilized humanoid foot found in South Africa is 1.7m years old and it had osteosarcoma.

Neoadjuvant

The term "neo-adjuvant therapy" (from the Latin adjuvare, meaning to help) refers to therapy that is carried out before the operation (= resection) of a tumor. A neo-adjuvant therapy can generally be chemotherapy, radiation therapy, or treatment using pre-operative targeted therapy. The goal of neo-adjuvant therapy is make the resection of a tumor as easy as possible (e.g. by reducing its size) or to reduce the operation’s scope to a minimum. It’s also referred to "downstaging" a tumour disease.

Palliative

Palliative treatment is the medical term for treatment that makes a disease easier to bear, in contrast to healing it.

adjuvant

Adjuvant treatment is a kind of "preventative therapy": After the complete removal of a tumor, adjuvant treatment is given as prophylaxis against recurrences. It aims to treat so called micro metastases that may be present but not yet visible, and therefore lower the risk of a recurrence. Adjuvant therapy is usually recommended for sarcoma patients, whose risk of recurrence – despite a successful operation – remains high.

GIST

Gastrointestinal stromal tumor (GIST) affects the digestive tract or nearby structures within the abdomen. The most common location is the stomach. GI stromal tumor, or GIST cancer, is a sarcoma.